


let the waters be deep

by kenopsia (indie)



Category: Sherlock (TV)
Genre: Brief mention of unbiological pregnancy, Frottage, M/M, Oral Sex, Sibling Incest
Language: English
Status: Completed
Published: 2014-02-08
Updated: 2014-02-08
Packaged: 2018-01-11 15:26:26
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,571
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1174696
Author URL: https://archiveofourown.org/users/indie/pseuds/kenopsia
Summary: <blockquote class="userstuff">
              <p>"I had thought... do you mind if I stay here? For a while?" Sherlock said, because he doesn't get it, has never gotten it.</p><p>Mycroft told him, "What's mine has always been yours."</p>
            </blockquote>





	let the waters be deep

**Author's Note:**

  * For [General_Button](https://archiveofourown.org/users/General_Button/gifts).



> This is pure filth. I am probably going to hell. Or jail. Or Helljail. I'm sorry I brought dishonor on China. 
> 
> (The only underage bit is the frottage.)

Sherlock and Mycroft hadn't indulged in physical contact with each other since Sherlock had come to him at nineteen, thrown out of Cambridge and devastated. He'd broken into Mycroft's flat; waited until the ambiguous hours between today and tomorrow to catch his brother unaware, and found himself disappointed to walk in on a Mycroft still (or already?) dressed in his suit like armor - shirtsleeves and coat and polished leather shoes that _snicked_ across the floor when Mycroft moved from his arm chair to Sherlock, looking lost in his lobby. He was chilled to the bone, past skin and blood, because he'd fled, ashamed, and he met his brother in the middle, pressing his frozen face into his brother’s neck.

Mycroft felt the urge to shush him, even though he wasn't making any noise, and quelled the impulse as a weak, nonsensical one, and instead he rubbed both hands up and down his back silently, with firm pressure before Sherlock's face tight against his skin turned from distraught child to something keener, sly eyed and hungry, open mouthed and hot. The mixed signals sensation between Sherlock's cold face and his hot mouth sent his stomach into a swirling mess of turmoil. "Sherlock," Mycroft said, because he was goal oriented to his grave, "we'll fix it."

"Don't talk right now," Sherlock said, and Mycroft had always been powerless to tell him no.

*

The first time, Sherlock had been fifteen and crawled in bed with him.

"You're too old for this, Sherlock." As a child, their parents had done everything they could to stop Sherlock from sucking his thumb. Their last attempt was a daily application of a bitter tasting polish to his nails. They'd considered the issue solved after that, but only because they had no idea he'd come to his brother after-hours to suck on Mycroft's fingers instead.

At fifteen, it hadn't happened in years, but here Sherlock was, snuggling into the parenthetical curve of Mycroft's body and commandeering his hand. The sensation, and soft sucking sounds hit Mycroft differently than they had when Sherlock had been five and Mycroft had been twelve.

Mycroft's heart slammed against his rib cage as he tried to stop the onslaught of images that fluttered through his brain, inappropriate images that left him feeling shocked and disgusting and so, so wanting. "Stop, Sherlock" Mycroft whispered, and Sherlock had twisted in his arms, ended up face to face with his brother with one leg wedged between his thighs, Sherlock’s leg halted about a millimeter from his startling erection. Mycroft could cry with shame.

"Stop what?" Sherlock had whispered, moving his leg to press against Mycroft's erection. "Everyone else is dull," he whispered. "It might as well be you. It might as well be... me." Sherlock didn't sound petulant, then. He sounded thoughtful. Sherlock moved his leg back an inch and Mycroft almost followed him, crowded towards him, but kept himself still, instead.

"Don't you want this?"

Mycroft could feel his pulse in his ears and he threads rhythm in his wrists. Everything in him was trying to remind him of propriety, of Westermarck, of what their poor mother would say if she knew.

What Mycroft said was, "you're a child, Sherlock."

"I'm smarter than any adult," Sherlock said. "You're my only friend, Mycroft."

Mycroft slammed his eyes shut and counted to ten. "You're not an adult, though, Sherlock, no matter how brilliant you are."

Sherlock looked disappointed. "Okay. We won't have sex," he said, casually, as if that had been an option on the table. Mycroft let out a huff of laughter.

"We'll just do this," he said, voice brightening, and brought himself flush against Mycroft again, doing a luxurious, full body write against him. The pressure against his cock put explosions beside his eyes and Sherlock, who'd never wanted anything he didn't reach for with both hands, had rubbed himself off against the soft flesh of Mycroft's hip and stomach, cotton pajamas pushed away from the damp heat of his cock.

*

He hadn’t had intercourse with him then because he was a child, and he’d bottled the incident away, putting distance between himself and his confused baby brother. When Sherlock had showed up at nineteen, he hadn’t either, though he'd laid Sherlock across his bed and sucked him to the edge of release until he'd been reduced to a sobbing wreck, and then Mycroft had kissed his year stained cheeks, touched his face and drew his fingers across what were unmistakably track marks, fading to various degrees.

Now though, his brother clean and bright eyed but so, so broken because he'd done what he wanted, as always, running towards the adventures of a dead man and now his best friend had moved on. Mycroft had deduced him from the moment he'd come in, eyes downcast and being well mannered with Anthea. He’d dismissed her with a subtle gesture.

"Please," Sherlock had said, half grown man and half child and Mycroft said: "come here."

Sherlock had new scars, new damage and Mycroft put his shoulder in his mouth. "You're mine. You're mine and I'm going to take care of you, always." Mycroft said, voice thick with emotion. "But we don't have to do this. I will always love you."

"If you don't," Sherlock said, "I may never forgive you."

*

He sank into the heat, his heart tight in his chest and his throat closed like a fist. "Mine," he whispered into his skin, feverish under his fingertips. It felt like the moment the plane touched the ground again and Mycroft was allowed to breathe again.

When he was completely seated, Sherlock's weedy legs wrapped around him in a vice grip. "Alright?"

"Nothing is alright," Sherlock moaned, pressing his wrist to his eyes.

Mycroft knew what he meant, but he thought he should check anyways. "Should I...?"

Instead of replying, Sherlock’s hips bucked up against him, spine snapping into an extreme arc, jolting against Mycroft's pelvis. "Don't. You. Dare."

Mycroft threw himself into it, rocking against Sherlock, sucking hard on his plump bottom lip and then his top, fingertips dragging artless touches across his back. He rocked into him with the helpless desperation of the lost, the sinners, the hopeless, and the brothers completely at a loss how to fix them, pounding with bruising force.

He stabilized himself with one hand planted by Sherlock's head while the other came down to rub his stomach, avoiding his flushed and wanting cock. It looked utterly kissable. Later, Mycroft decided. If he were to drown anyway, let the waters be deep.

He kept up his rough intensity, mocked and undermined by the way he looked at Sherlock as if he might break or he was already broken. Perhaps somewhere in between the two. Mycroft dragged his stubbled chin down the side of his face, neck, flushed chest, scraping hard against his left nipple.

"Ah!" Sherlock said, surprised, and used his crossed ankles at the small of Mycroft's back to tighten his grip and grind his arse closer, as if they still weren't close enough.

Mycroft was always prepared to give his brother what he wanted, even if it killed him. He thought he'd been formidable before, but now as he slammed into his brother, again and again and again, he was something like a force of nature. A tidal wave of sensation and pressing hands and Sherlock's stuttering cries of _yes_ and _please_ and Mycroft's own name like it was something that might rescue him.

Mycroft felt the pressure building in his belly, like heat and fury but so delicious, and he spent the last few minutes punctuating his furious electrified thrusting with long, tight-gripped pulls on Sherlock's drenched cock, red with neglect and so gorged with blood there was no give in his hand.

When it was done, he kissed Sherlock's sweat soaked curls, touched him through his after-tremors and twitches with his fingertips down his side, cleaned him up, expecting any moment the return of his surly brother. He never arrived.

In the morning Mycroft dressed and put himself back together like he is putting on a different person. He cannot afford to be so shaken with a terrorist cell looming over his week like a foul cloud.

Sherlock was awake when he left, sitting on Mycroft's bed with his bare knees under his chin, looking like a lost child. "We'll get your John back, Sherlock," he said, as kindly as he could manage.

It didn't happen the night before, but Mycroft was sure that by the time he returned in the evening Sherlock would be gone like an ephemeral thing, leaving only the scent of him lingering in his bed and lumps in Mycroft's throat. He expects them to ignore the frisson of whatever damaged, ion-aligning, charged _thing_ between the two of them for another decade. Instead, he finds Sherlock shredding lettuce in his forty-thousand pound kitchen, a sharp knife against his marble countertops with no cutting board, and dropping a teaspoon of each into different tea cups he has laid out, half full of assorted liquids.

"Sorry," Sherlock said sheepishly, and you could knock Mycroft over with a strong wind. "I've been wanting to run this experiment for months."

Sherlock looks well rested. He looks well kept. He looks ... happy. Mycroft moves to him, near but not too near, not near enough to be rustled by Sherlock's long exhalations. "So," Mycroft says.

"I had thought... do you mind if I stay here? For a while?" Sherlock said, because he doesn't get it, has never gotten it.

Mycroft told him, "What's mine has always been yours."

Mycroft went to look over his papers, filing away important bits and searching underneath the stated for subtextual patterns and the afternoon slipped unnoticed into evening, and then midnight arrived with the gong of his old grandfather clock, and Mycroft began to bundle himself up for bed, leaving his door open in a stupid, stupid hope. Hating himself for wanting but wanting all the same. It felt different now than it had when Sherlock was nineteen, because he’d seen his brother incapacitate a man with nothing but a grip on his hand.

*

When he crept in, Sherlock didn't curl into his negative space. Instead, Sherlock planted himself behind Mycroft, slotting around him, reaching one hand around to find Mycroft's soft cock, which became immediately interested, and filled out as Sherlock curled one hand around it, his thumb petting rhythmically across the head.

Sherlock's hand left him for a moment, and Mycroft accidentally let out a noise of soft longing. "Impatient," Sherlock chuckled, and Mycroft could hear him trying to work open a condom. "I was stupid, last time, not to have one," he explained, and after he fussed with it for long minutes, Mycroft turned over and snatched the packet from him, twisting it open expertly.

"Not sure at what point on your trip you lost all coordination," Mycroft teased, but Sherlock looked unapologetic.

"Sorry. I've never used one before." Mycroft didn't know what to say, to tease or to comfort, so he did neither. Instead he merely rolled  it onto his brother's flesh with a grin. "First time for everything."

*

Sherlock, at some point, had effectively moved back in to Mycroft's house, and for the first time since Sherlock was a teenager, they were cohabitating. It was Mycroft's dirty secret and sly thrill. He thought about him constantly, had to recalibrate his mental processing to allocate a percentage to think of him concurrently with whatever else he had at the forefront.

When Mycroft asked him about his friend, Sherlock shrugged. "John will come around," he said. "He needs space and time. I did not handle my return very well." Which was quite possibly the most grown up thing Sherlock had ever said.

*

Six weeks later, Mycroft came home to find his house in complete and utter chaos.

"What is the meaning of this?" he demanded. Sherlock had pushed all of the furniture in his formal sitting room to one side, and there were papers everywhere. He looked distraught, hair unkempt and still in his pajamas.

"I cannot possibly interact with you, right now, Mycroft."

Mycroft picked up one of the sheets from the ground with his thumb and index finger. "Oh." he said. "Oh is right," Sherlock snarled, pushing papers out of the way only to fill the space with even more papers.

"It..." Mycroft said after a long while, "is not the worst thing that could have happened."

"We share a mother," Sherlock said, putting his head in his hands. There were pundit squares on every flat surface in the room.

Something in Mycroft was nastily, secretly delighted. He looked at Sherlock and became hard faster than he had since his adolescence.

"Let me take you to bed," Mycroft said, in a low voice he possessed but didn't use as often as Sherlock.

Mycroft laid him out and licked at him for a long time, losing track of time; he sucked happily like a child with a sweet, rubbed his face across Sherlock's stomach like an errant pet, with Sherlock throwing his head back and forth, moaning weakly as he'd lost all energy to do anything but.

Mycroft had already come in his trousers once, and was getting roused again, four fingers twisting inside of his brother, pounding relentlessly against his prostate as he removed all stimulation from Sherlock's cock, pressing his fingers against his bladder, fondling his testicles, sucking livid, merciless bruises from the crease of Sherlock's groin to the side of his knee, pressing his legs wide and overwhelming his brother from everywhere at once. It was something Mycroft was fond of; they both were, and he could ignore his own body's wants in favor of Sherlock's indefinitely.

"I am guessing," Sherlock rasped with a voice like sandpaper, and a pointed look at Mycroft's scorching, powerful errection, still wet with his own ejaculate, "that you are not unhappy with the prospect of a child."

There will be complications, and we will have to invent a father," Mycroft said, amused that Sherlock could barely keep his eyes open, despite the seeping precome and his as-yet unsatisfied, neglected genitals. He decided to have pity on his brother and crouched above him, knees to each side of him before gracelessly lowering himself down to seat himself on Sherlock's hips, aligning their penises and wrapping both hands around them in a vice grip, their press and crash of friction finally blurring Mycroft's mind in a way that was pleasantly, desperately delicious. "But," he huffed, pumping and gyrating on his brother, weak as a kitten, hands scrabbling in the sheets but unable to find any sort of purchase. "when have we ever done anything simple?"

Sherlock ejaculated with a great stream of unintelligible noises with very few words, finding an ounce of strength to buck upwards as he did, but Mycroft kept his position on his hips. There was a great deal of come to deal with, which Mycroft did efficiently with a pillowcase he destined for the rubbish bin first thing in the morning, and then covered Sherlock with his own body once more, draping from head to toe, entirely to stifling, but he couldn't think of anywhere else he could possibly be at the moment than between Sherlock and everything that wasn't his bed, cocks softening against each other and breathing synched up as it had been for their entire lives. 

**Author's Note:**

> For GB, who is like a tiny demon.


End file.
